MMC and LD simulations of alpha-D-Glcp-(1-->2)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-OMe. A model for the terminal trisaccharide in glycoprotein precursors.

The conformational flexibility and the dynamics of alpha-D-Glcp-(1-->2)-alpha-D-Glcp(1-->3)-alpha-D-Glcp-OMe (I) has been investigated by Metropolis-Monte Carlo with the HSEA (Hard Sphere Exo-Anomeric) force field and Langevin dynamics simulations employing two different CHARMm (Chemistry at HARvard Molecular Mechanics) force fields, CHEAT95 and PARM22. The conformational space spanned by the molecule is similar for the two former force fields but differ significantly for the latter. Hydrogen bonding between O2" and O4 of the title compound is analysed in comparison to NMR and preliminary results from X-ray powder diffraction studies.